Subsurface and Office Representation in Mining Geology 



1031 



Quantitative representation is by line symbol (and circle) indicating 

 width (fig. 542). On plan maps a simple semi-decimal system, based on 

 number and width of lines, indicates width of veins. Representation, 

 posted with ruling pen and French curve, is superimposed on the vein 

 geologic representation. Circular symbols represent metallization width 

 on longitudinal section, and accessory metals on plan; this representation, 

 posted with a drop-circle pen, is adjacent to major metals linear represen- 

 tation. Qualitative representation is by color. Width symbols are posted 

 in color to indicate grade. Ore reserve blocks are posted in semi-permanent 

 colored ink on the metallization overlay maps; the color indicates grade 



METALLIZATION LEGEND 



Quantitative (Width) 



Qualitative (Grade) 



^" 



General 

 Symbols 



Accessory 



Metols 

 Long. Sec 



Grade 



Oz. Ag 



% 



Cu.Pb.Zn 



Colors 



o 



© 



O 



@ 



Orange 



Yellow Green 



Red Purple 



Metallization representation synnbols are colored lines indicating grade 

 and width. Ttie predominant economic metollizalion is represented 

 by ttie yellow - red color range. Ttiree metallizations are chroma- 

 tically represented thus: (Cu) ( Zn) (Cu) (Pb) (Zn) (Cu) (Pb) (Zn). 

 Accessory metals ore indicated adjacent to linear representation 

 by grade colored circular symbols. 



Figure 542. Assay-metallization symbols as indicated, posted on plastic overlay sheets. 



classification. When revision erasures are necessary, the plastic is resur- 

 faced by "painting" with acetone. 

 Recording and Posting Specifications 



Standardization of note-sheet recording and map posting is impera- 

 tive, so that there is sufficient space for legible, factual, detailed recording 

 and resultant effective utilization. 



General Specifications — The subsurface mapping plane is shoulder- 

 high; structures above and below this plane are projected to this elevation 

 and represented at the mapping-plane intersection. 



All culture and engineering data (contour pen excavation lines and 

 LeRoy-lettered descriptive data) are posted on the reverse, or glazed side 

 of tracing-cloth office maps. Descriptive geologic side notes and assays 

 are lettered free-hand on the unglazed side. 



Lithology — The lithic, graphic, geologic representation is usually 

 superimposed on the entire subsurface-excavation area, and extends Vs'' 

 outside the ground or excavation lines. If the excavation is lagged or 



